A ball of mass 6.5 g is moving with a velocity of 2.5 m/s strikes with another ball of mass of 4.5 g. What is the combined velocity of both the balls?
(2 Marks)

Given data
The mass of the first ball is m = 6.5 g
The initial velocity of the first ball is u = 2.5 m/s
The mass of the second ball is M = 4.5 g
The initial velocity of the second ball is v = 0 m/s

The formula for the conservation of momentum is given as
mu + Mv = (m + M)V
[1 Mark]

Substitute the known values in the above expression as
(6.5)(2.5) + (4.5)(0) = (6.5 + 4.5) V
V = 1.48 m/s
[1 Mark]

Hence, the combined velocity of both the balls is V = 1.48 m/s.